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XCHART Statement |
See CUSONES1 in the SAS/QC Sample Library |
This example shows how the cusum parameters saved in the previous example can be applied to new measurements saved in a data set named CANS2:
data cans2; length pump $ 8; label hour = 'Hour'; input hour weight pump $ 8. ; datalines; 16 8.1765 Pump 3 17 8.0949 Pump 3 18 8.1393 Pump 3 19 8.1491 Pump 3 20 8.0473 Pump 1 21 8.1602 Pump 1 22 8.0633 Pump 1 23 8.0921 Pump 1 24 8.1573 Pump 1 25 8.1304 Pump 1 26 8.0979 Pump 1 27 8.2407 Pump 1 28 8.0730 Pump 1 29 8.0986 Pump 2 30 8.0785 Pump 2 31 8.2308 Pump 2 32 8.0986 Pump 2 33 8.0782 Pump 2 34 8.1435 Pump 2 35 8.0666 Pump 2 ;
The following statements create a one-sided cusum chart for the measurements in CANS2 using the parameters in CUSPARM:
title "One-Sided Cusum Analysis for New Data"; proc cusum data=cans2 limits=cusparm; xchart weight*hour ( pump )/ cblocklab = ligr cinfill = ywh cframe = bigb cconnect = salmon climits = black; label weight = 'Cusum of Weight'; run;
The LIMITS= option in the PROC CUSUM statement specifies the data set containing preestablished cusum parameters.* The chart, shown in Figure 12.11, indicates that the process is in control. Levels of the variable PUMP (referred to as a block-variable) do not enter into the analysis but are displayed in a block legend across the top of the chart. See "Block Variable Legend Options" in Table 12.7.
In general, the parameters for a specified process and subgroup-variable are read from the first observation in the LIMITS= data set for which
If you are maintaining more than one set of cusum parameters for a particular process, you will find it convenient to include a special identifier variable named _INDEX_ in the LIMITS= data set. This must be a character variable of length 16. Then, if you specify READINDEX='value' in the XCHART statement, the parameters for a specified process and subgroup-variable are read from the first observation in the LIMITS= data set for which
In this example, the LIMITS= data set was created in a previous run of the CUSUM procedure. You can also create a LIMITS= data set with the DATA step. See "LIMITS= Data Set" for details concerning the variables that you must provide.
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